Method and device for performing sl drx operation on basis of harq feedback in nr v2x

ABSTRACT

Presented in one embodiment is a method by which a first device performs wireless communication. The method may comprise the steps of: acquiring a sidelink discontinuous reception (SL DRX) configuration; receiving, from a second device, first sidelink control information (SCI) for scheduling a first physical sidelink shared channel (PSSCH) through a first physical sidelink control channel (PSCCH); receiving, from the second device, second SCI and first data through the first physical sidelink shared channel (PSSCH); and determining a first physical sidelink feedback channel (PSFCH) resource on the basis of a slot index and a sub-channel index, which are related to the first PSSCH. For example, a first timer included in the SL DRX configuration can be initiated on the basis of the omission of a first PSFCH transmission related to the first PSSCH on the first PSFCH resource.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/KR2022/000521, filed on Jan. 12, 2022, which claims the benefit ofearlier filing date and right of priority to Korean Patent ApplicationNo. 10-2021-0004269, filed on Jan. 12, 2021, the contents of all ofwhich are hereby incorporated by reference herein in their entireties.

TECHNICAL FIELD

This disclosure relates to a wireless communication system.

BACKGROUND

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic. Vehicle-to-everything (V2X) refers to a communicationtechnology through which a vehicle exchanges information with anothervehicle, a pedestrian, an object having an infrastructure (or infra)established therein, and so on. The V2X may be divided into 4 types,such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

SUMMARY

Meanwhile, in a sidelink communication, a UE may perform a sidelinkdiscontinuous reception (SLDRX) operation to save power of the UE. Forexample, in an SL hybrid automatic repeat request (HARQ) feedbackoperation that transmits only a negative acknowledgment (NACK), when thereceiving UE performing the SL DRX operation skips/omits the NACKtransmission, the transmitting UE may not perform an additionalretransmission operation by assuming that the receiving UE hassuccessfully received the MAC protocol data unit (PDU). On the otherhand, since the receiving UE has not yet succeeded in receiving the MACPDU, a problem of re-setting or extending the SL DRX timer may occur.

In addition, for example, in the SL HARQ feedback operation fortransmitting an ACK and a NACK, when the receiving UE performing the SLDRX operation skips/omits the ACK transmission, the transmittingterminal may assume that the receiving UE has not received the MAC PDUand perform an additional retransmission operation. On the other hand,since the receiving UE succeeds in receiving the MAC PDU, a problem ofnot re-setting or extending the SL DRX timer may occur.

According to an embodiment of the present disclosure, a method for afirst device to perform wireless communication is proposed. The methodcomprises: obtaining a sidelink discontinuous reception (SL DRX)configuration; receiving first sidelink control information (SCI) forscheduling a first physical sidelink shared channel (PSSCH) through afirst physical sidelink control channel (PSCCH) from a second device;receiving second SCI and first data from the second device through thefirst PSSCH; and determining a first physical sidelink feedback channel(PSFCH) resource based on an index of a slot and an index of asubchannel which are related to the first PSSCH, wherein a first timerincluded in the SL DRX configuration is started based on skipping of afirst PSFCH transmission related to the first PSSCH on the first PSFCHresource. For example, a first timer included in the SL DRXconfiguration is started based on skipping of a first PSFCH transmissionrelated to the first PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a first device forperforming wireless communication may be provided. For example, thefirst device may include one or more memories for storing instructions;one or more transceivers; and one or more processors connecting the oneor more memories and the one or more transceivers. For example, the oneor more processors execute the instructions to obtain a sidelinkdiscontinuous reception (SL DRX) configuration; receive first sidelinkcontrol information (SCI) for scheduling a first physical sidelinkshared channel (PSSCH) through a first physical sidelink control channel(PSCCH) from a second device; and receiving second SCI and first datafrom the second device through the first PSSCH; and determine a firstphysical sidelink feedback channel (PSFCH) resource based on an index ofa slot and an index of a subchannel which are related to the firstPSSCH. For example, a first timer included in the SL DRX configurationis started based on skipping of a first PSFCH transmission related tothe first PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, an apparatusconfigured to control the first UE may be provided. For example, one ormore processors; and one or more memories operably coupled by the one ormore processors and storing instructions. For example, the one or moreprocessors execute the instructions to obtain a sidelink discontinuousreception (SL DRX) configuration; receive first sidelink controlinformation (SCI) for scheduling a first physical sidelink sharedchannel (PSSCH) through a first physical sidelink control channel(PSCCH) from a second UE; receive second SCI and first data from thesecond UE through the first PSSCH; and determine a first physicalsidelink feedback channel (PSFCH) resource based on an index of a slotand an index of a subchannel which are related to the first PSSCH. Forexample, wherein a first timer included in the SL DRX configuration isstarted based on skipping of a first PSFCH transmission related to thefirst PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a non-transitorycomputer readable medium (CRM) storing instructions may be provided. Forexample, the instructions, when executed, cause the first device to:obtain a sidelink discontinuous reception (SL DRX) configuration;receive first sidelink control information (SCI) for scheduling a firstphysical sidelink shared channel (PSSCH) through a first physicalsidelink control channel (PSCCH) from a second device; receive secondSCI and first data from the second device through the first PSSCH; anddetermine a first physical sidelink feedback channel (PSFCH) resourcebased on an index of a slot and an index of a subchannel which arerelated to the first PSSCH. For example, a first timer included in theSL DRX configuration is started based on skipping of a first PSFCHtransmission related to the first PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a method for asecond device to perform wireless communication is proposed. The methodcomprises: transmitting first sidelink control information (SCI) forscheduling a first physical sidelink shared channel (PSSCH) through afirst physical sidelink control channel (PSCCH) to a first device; andtransmitting second SCI and first data to the first device through thefirst PSSCH. For example, a sidelink discontinuous reception (SL DRX)configuration is obtained. For example, wherein a first physicalsidelink feedback channel (PSFCH) resource is determined based on anindex of a slot and an index of a subchannel which are related to thefirst PSSCH. For example, wherein a first timer included in the SL DRXconfiguration is started based on skipping of a first PSFCH transmissionrelated to the first PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a second devicefor performing wireless communication may be provided. For example, thesecond device may include one or more memories to store instructions;one or more transceivers; and one or more processors connecting the oneor more memories and the one or more transceivers. For example, the oneor more processors execute the instructions to transmit first sidelinkcontrol information (SCI) for scheduling a first physical sidelinkshared channel (PSSCH) through a first physical sidelink control channel(PSCCH) to a first device; and transmit second SCI and first data to thefirst device through the first PSSCH. For example, a sidelinkdiscontinuous reception (SL DRX) configuration is obtained. For example,a first physical sidelink feedback channel (PSFCH) resource isdetermined based on an index of a slot and an index of a subchannelwhich are related to the first PSSCH. For example, a first timerincluded in the SL DRX configuration is started based on skipping of afirst PSFCH transmission related to the first PSSCH on the first PSFCHresource.

In ACK/NACK-based hybrid automatic repeat request (HARQ) feedback, whena physical sidelink feedback channel (PSFCH) transmission isskipped/omitted, by preventing the transmitting UE from repeatingretransmission by mistakenly being a negative acknowledgment (NACK),efficient SL communication can be performed.

In addition, in HARQ feedback for transmitting only a NACK, when thePSFCH transmission is skipped/omitted, by not starting the SL DRX timer,there can be efficient features in terms of power saving.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure.

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 6 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 9 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 10 shows a method in which a UE that has reserved transmissionresource(s) informs another UE of the transmission resource(s), based onan embodiment of the present disclosure.

FIG. 11 shows a procedure for a receiving UE to start an SL DRX-relatedtimer according to an embodiment of the present disclosure.

FIG. 12 shows another procedure in which a receiving UE starts an SLDRX-related timer according to an embodiment of the present disclosure.

FIG. 13 shows an example of a reserved resource in which a receiving UEis located after an SL DRX-related timer expires, according to anembodiment of the present disclosure.

FIG. 14 shows a method for a first device to start an SL DRX-relatedtimer, according to an embodiment of the present disclosure.

FIG. 15 shows a method for starting an SL DRX timer according to anembodiment of the present disclosure.

FIG. 16 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 17 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 18 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 19 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 20 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 21 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DETAILED DESCRIPTION

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B, C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean“A, B, or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control information”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16 m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRAis part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 2 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer exchanges an RRC message betweenthe UE and the BS.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 3 may be combined withvarious embodiments of the present disclosure. Specifically, (a) of FIG.3 shows a radio protocol stack of a user plane for Uu communication, and(b) of FIG. 3 shows a radio protocol stack of a control plane for Uucommunication. (c) of FIG. 3 shows a radio protocol stack of a userplane for SL communication, and (d) of FIG. 3 shows a radio protocolstack of a control plane for SL communication.

Referring to FIG. 3 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., a MAC layer, an RLC layer, a packetdata convergence protocol (PDCP) layer, and a service data adaptationprotocol (SDAP) layer) for data delivery between the UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, an RRC_INACTIVE state is additionally defined, and a UE being in the RRC_INACTIVE state may maintain its connection with a core network whereasits connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.

Referring to FIG. 4 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot)symb), a number slots per frame (N^(frame,u)slot), and anumber of slots per subframe (N^(subframe,u)slot) based on an SCSconfiguration (u), in a case where a normal CP is used.

TABLE 1 SCS (15*2^(u)) N^(slot) _(s) _(y) _(mb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u=0) 14 10 1 30 KHz (u=1) 14 20 2 60 KHz(u=2) 14 40 4 120 KHz (u=3) 14 80 8 240 KHz (u=4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u=2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 450 MHz - 6000 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 410 MHz - 7125 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 5 may becombined with various embodiments of the present disclosure.

Referring to FIG. 5 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel state information -reference signal (CSI-RS) (excluding RRM) outside the active DL BWP. Forexample, the UE may not trigger a channel state information (CSI) reportfor the inactive DL BWP. For example, the UE may not transmit physicaluplink control channel (PUCCH) or physical uplink shared channel (PUSCH)outside an active UL BWP. For example, in a downlink case, the initialBWP may be given as a consecutive RB set for a remaining minimum systeminformation (RMSI) control resource set (CORESET) (configured byphysical broadcast channel (PBCH)). For example, in an uplink case, theinitial BWP may be given by system information block (SIB) for a randomaccess procedure. For example, the default BWP may be configured by ahigher layer. For example, an initial value of the default BWP may be aninitial DL BWP. For energy saving, if the UE fails to detect downlinkcontrol information (DCI) during a specific period, the UE may switchthe active BWP of the UE to the default BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. For example, the UE may receive a configuration for theUu BWP from the BS/network. The SL BWP may be (pre-)configured in acarrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE.For the UE in the RRC_CONNECTED mode, at least one SL BWP may beactivated in the carrier.

FIG. 6 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 6 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 6 that the number of BWPs is 3.

Referring to FIG. 6 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

A sidelink synchronization signal (SLSS) may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS), as an SL-specific sequence. The PSSS may be referred toas a sidelink primary synchronization signal (S-PSS), and the SSSS maybe referred to as a sidelink secondary synchronization signal (S-SSS).For example, length-127 M-sequences may be used for the S-PSS, andlength-127 gold sequences may be used for the S-SSS. For example, a UEmay use the S-PSS for initial signal detection and for synchronizationacquisition. For example, the UE may use the S-PSS and the S-SSS foracquisition of detailed synchronization and for detection of asynchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure. The embodiment of FIG. 7 may becombined with various embodiments of the present disclosure.

Referring to FIG. 7 , in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit an SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 8 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, (a) of FIG. 8 shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, (a) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, (b) of FIG. 8 shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, (b) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 2.

Referring to (a) of FIG. 8 , in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (e.g., downlink control information (DCI)) or RRC signaling (e.g.,Configured Grant Type 1 or Configured Grant Type 2), and the UE 1 mayperform V2X or SL communication with respect to a UE 2 according to theresource scheduling. For example, the UE 1 may transmit a sidelinkcontrol information (SCI) to the UE 2 through a physical sidelinkcontrol channel (PSCCH), and thereafter transmit data based on the SCIto the UE 2 through a physical sidelink shared channel (PSSCH).

Referring to (b) of FIG. 8 , in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

FIG. 9 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 9 may be combined with variousembodiments of the present disclosure. Specifically, (a) of FIG. 9 showsbroadcast-type SL communication, (b) of FIG. 9 shows unicast type-SLcommunication, and (c) of FIG. 9 shows groupcast-type SL communication.In case of the unicast-type SL communication, a UE may performone-to-one communication with respect to another UE. In case of thegroupcast-type SL transmission, the UE may perform SL communication withrespect to one or more UEs in a group to which the UE belongs. Invarious embodiments of the present disclosure, SL groupcastcommunication may be replaced with SL multicast communication, SLone-to-many communication, or the like.

Meanwhile, in the present disclosure, for example, a transmitting UE (TXUE) may be a UE which transmits data to a (target) receiving UE (RX UE).For example, the TX UE may be a UE which performs PSCCH transmissionand/or PSSCH transmission. Additionally/alternatively, for example, theTX UE may be a UE which transmits SL CSI-RS(s) and/or a SL CSI reportrequest indicator to the (target) RX UE. Additionally/alternatively, forexample, the TX UE may be a UE which transmits a (control) channel(e.g., PSCCH, PSSCH, etc.) and/or reference signal(s) on the (control)channel (e.g., DM-RS, CSI-RS, etc.), to be used for a SL RLM operationand/or a SL RLF operation of the (target) RX UE.

Meanwhile, in the present disclosure, for example, a receiving UE (RXUE) may be a UE which transmits SL HARQ feedback to a transmitting UE(TX UE) based on whether decoding of data received from the TX UE issuccessful and/or whether detection/decoding of a PSCCH (related toPSSCH scheduling) transmitted by the TX UE is successful.Additionally/alternatively, for example, the RX UE may be a UE whichperforms SL CSI transmission to the TX UE based on SL CSI-RS(s) and/or aSL CSI report request indicator received from the TX UE.Additionally/alternatively, for example, the RX UE is a UE whichtransmits a SL (L1) reference signal received power (RSRP) measurementvalue, to the TX UE, measured based on (pre-defined) reference signal(s)and/or a SL (L1) RSRP report request indicator received from the TX UE.Additionally/alternatively, for example, the RX UE may be a UE whichtransmits data of the RX UE to the TX UE. Additionally/alternatively,for example, the RX UE may be a UE which performs a SL RLM operationand/or a SL RLF operation based on a (pre-configured) (control) channeland/or reference signal(s) on the (control) channel received from the TXUE.

Meanwhile, in the present disclosure, for example, in case the RX UEtransmits SL HARQ feedback information for a PSSCH and/or a PSCCHreceived from the TX UE, the following options or some of the followingoptions may be considered. Herein, for example, the following options orsome of the following options may be limitedly applied only if the RX UEsuccessfully decodes/detects a PSCCH scheduling a PSSCH.

(1) groupcast option 1: no acknowledgement (NACK) information may betransmitted to the TX UE only if the RX UE fails to decode/receive thePSSCH received from the TX UE.

(2) groupcast option 2: If the RX UE succeeds in decoding/receiving thePSSCH received from the TX UE, ACK information may be transmitted to theTX UE, and if the RX UE fails to decode/receive the PSSCH, NACKinformation may be transmitted to the TX UE.

Meanwhile, in the present disclosure, for example, the TX UE maytransmit the following information or some of the following informationto the RX UE through SCI(s). Herein, for example, the TX UE may transmitsome or all of the following information to the RX UE through a firstSCI and/or a second SCI.

-   PSSCH (and/or PSCCH) related resource allocation information (e.g.,    the location/number of time/frequency resources, resource    reservation information (e.g., period))-   SL CSI report request indicator or SL (L1) reference signal received    power (RSRP) (and/or SL (L1) reference signal received quality    (RSRQ) and/or SL (L1) reference signal strength indicator (RSSI))    report request indicator-   SL CSI transmission indicator (or SL (L1) RSRP (and/or SL (L1) RSRQ    and/or SL (L1) RSSI) information transmission indicator) (on a    PSSCH)-   Modulation and Coding Scheme (MCS) information-   TX power information-   L1 destination ID information and/or L1 source ID information-   SL HARQ process ID information-   New Data Indicator (NDI) information-   Redundancy Version (RV) information-   (Transmission traffic/packet related) QoS information (e.g.,    priority information)-   SL CSI-RS transmission indicator or information on the number of    antenna ports for (transmitting) SL CSI-RS-   TX UE location information or location (or distance range)    information of the target RX UE (for which SL HARQ feedback is    requested)-   Reference signal (e.g., DM-RS, etc.) information related to decoding    (and/or channel estimation) of data transmitted through a PSSCH. For    example, information related to a pattern of (time-frequency)    mapping resources of DM-RS(s), RANK information, antenna port index    information, information on the number of antenna ports, etc.

Meanwhile, in the present disclosure, for example, since the TX UE maytransmit a SCI, a first SCI and/or a second SCI to the RX UE through aPSCCH, the PSCCH may be replaced/substituted with the SCI and/or thefirst SCI and/or the second SCI. Additionally/alternatively, the SCI maybe replaced/substituted with the PSCCH and/or the first SCI and/or thesecond SCI. Additionally/alternatively, for example, since the TX UE maytransmit a second SCI to the RX UE through a PSSCH, the PSSCH may bereplaced/substituted with the second SCI.

Meanwhile, in the present disclosure, for example, if SCI configurationfields are divided into two groups in consideration of a (relatively)high SCI payload size, the first SCI including a first SCI configurationfield group may be referred to as a 1 ^(st) SCI, and the second SCIincluding a second SCI configuration field group may be referred to as a2^(nd) SCI. Also, for example, the 1 ^(st) SCI may be transmitted to thereceiving UE through a PSCCH. Also, for example, the 2^(nd) SCI may betransmitted to the receiving UE through a (independent) PSCCH or may bepiggybacked and transmitted together with data through a PSSCH.

Meanwhile, in the present disclosure, for example, the term“configure/configured” or the term “define/defined” may refer to(pre)configuration from a base station or a network (through pre-definedsignaling (e.g., SIB, MAC, RRC, etc.)) (for each resource pool).

Meanwhile, in the present disclosure, for example, since an RLF may bedetermined based on out-of-synch (OOS) indicator(s) or in-synch (IS)indicator(s), the RLF may be replaced/substituted with out-of-synch(OOS) indicator(s) or in-synch (IS) indicator(s).

Meanwhile, in the present disclosure, for example, an RB may bereplaced/substituted with a subcarrier. Also, in the present disclosure,for example, a packet or a traffic may be replaced/substituted with a TBor a MAC PDU based on a transmission layer.

Meanwhile, in the present disclosure, a CBG may be replaced/substitutedwith a TB.

Meanwhile, in the present disclosure, for example, a source ID may bereplaced/substituted with a destination ID.

Meanwhile, in the present disclosure, for example, an L1 ID may bereplaced/substituted with an L2 ID. For example, the L1 ID may be an L1source ID or an L1 destination ID. For example, the L2 ID may be an L2source ID or an L2 destination ID.

Meanwhile, in the present disclosure, for example, an operation of thetransmitting UE to reserve/select/determine retransmission resource(s)may include: an operation of the transmitting UE toreserve/select/determine potential retransmission resource(s) for whichactual use will be determined based on SL HARQ feedback informationreceived from the receiving UE.

Meanwhile, in the present disclosure, a sub-selection window may bereplaced/substituted with a selection window and/or the pre-configurednumber of resource sets within the selection window, or vice versa.

Meanwhile, in the present disclosure, SL MODE 1 may refer to a resourceallocation method or a communication method in which a base stationdirectly schedules SL transmission resource(s) for a TX UE throughpre-defined signaling (e.g., DCI or RRC message). For example, SL MODE 2may refer to a resource allocation method or a communication method inwhich a UE independently selects SL transmission resource(s) in aresource pool pre-configured or configured from a base station or anetwork. For example, a UE performing SL communication based on SL MODE1 may be referred to as a MODE 1 UE or MODE 1 TX UE, and a UE performingSL communication based on SL MODE 2 may be referred to as a MODE 2 UE orMODE 2 TX UE.

Meanwhile, in the present disclosure, for example, a dynamic grant (DG)may be replaced/substituted with a configured grant (CG) and/or asemi-persistent scheduling (SPS) grant, or vice versa. For example, theDG may be replaced/substituted with a combination of the CG and the SPSgrant, or vice versa. For example, the CG may include at least one of aconfigured grant (CG) type 1 and/or a configured grant (CG) type 2. Forexample, in the CG type 1, a grant may be provided by RRC signaling andmay be stored as a configured grant. For example, in the CG type 2, agrant may be provided by a PDCCH, and may be stored or deleted as aconfigured grant based on L1 signaling indicating activation ordeactivation of the grant.

Meanwhile, in the present disclosure, a channel may bereplaced/substituted with a signal, or vice versa. For example,transmission/reception of a channel may include transmission/receptionof a signal. For example, transmission/reception of a signal may includetransmission/reception of a channel. In addition, for example, cast maybe replaced/substituted with at least one of unicast, groupcast, and/orbroadcast, or vice versa. For example, a cast type may bereplaced/substituted with at least one of unicast, groupcast, and/orbroadcast, or vice versa.

Meanwhile, in the present disclosure, a resource may bereplaced/substituted with a slot or a symbol, or vice versa. Forexample, the resource may include a slot and/or a symbol.

Meanwhile, in the present disclosure, a priority may bereplaced/substituted with at least one of logical channel prioritization(LCP), latency, reliability, minimum required communication range, proseper-packet priority (PPPP), sidelink radio bearer (SLRB), QoS profile,QoS parameter and/or requirement, or vice versa.

Meanwhile, in various embodiments of the present disclosure, a reservedresource and/or a selected resource may be replaced with a sidelinkgrant (SL GRANT).

Meanwhile, in various embodiments of the present disclosure, latency maybe replaced with a packet delay budget (PDB).

Meanwhile, in various embodiments of the present disclosure, a messagefor triggering a report on sidelink channel state information/sidelinkchannel quality information (hereinafter, SL_CSI information) may bereplaced with reception of sidelink channel state information referencesignal (CSI-RS).

Meanwhile, in the present disclosure, blind retransmission may referthat the TX UE performs retransmission without receiving SL HARQfeedback information from the RX UE. For example, SL HARQ feedback-basedretransmission may refer that the TX UE determines whether to performretransmission based on SL HARQ feedback information received from theRX UE. For example, if the TX UE receives NACK and/or DTX informationfrom the RX UE, the TX UE may perform retransmission to the RX UE.

Meanwhile, in the present disclosure, for example, for convenience ofdescription, a (physical) channel used when a RX UE transmits at leastone of the following information to a TX UE may be referred to as aPSFCH.

-   SL HARQ feedback, SL CSI, SL (L1) RSRP

Meanwhile, in the present disclosure, a Uu channel may include a ULchannel and/or a DL channel. For example, the UL channel may include aPUSCH, a PUCCH, a sounding reference Signal (SRS), etc. For example, theDL channel may include a PDCCH, a PDSCH, a PSS/SSS, etc. For example, aSL channel may include a PSCCH, a PSSCH, a PSFCH, a PSBCH, a PSSS/SSSS,etc.

Meanwhile, in NR V2X communication or NR sidelink communication, atransmitting UE may reserve/select one or more transmission resourcesfor sidelink transmission (e.g., initial transmission and/orretransmission), and the transmitting UE may transmit information on thelocation of the one or more transmission resources to receiving UE(s).

Meanwhile, when performing sidelink communication, a method for atransmitting UE to reserve or pre-determine transmission resource(s) forreceiving UE(s) may be representatively as follows.

For example, the transmitting UE may perform a reservation oftransmission resource(s) based on a chain. Specifically, for example, ifthe transmitting UE reserves K transmission resources, the transmittingUE may transmit location information for less than K transmissionresources to receiving UE(s) through a SCI transmitted to the receivingUE(s) at any (or specific) transmission time or a time resource. Thatis, for example, the SCI may include location information for less thanthe K transmission resources. Alternatively, for example, if thetransmitting UE reserves K transmission resources related to a specificTB, the transmitting UE may transmit location information for less thanK transmission resources to receiving UE(s) through a SCI transmitted tothe receiving UE(s) at any (or specific) transmission time or a timeresource. That is, the SCI may include location information for lessthan the K transmission resources. In this case, for example, it ispossible to prevent performance degradation due to an excessive increasein payloads of the SCI, by signaling only the location information forless than K transmission resources to the receiving UE(s) through oneSCI transmitted at any (or specific) transmission time or the timeresource by the transmitting UE.

FIG. 10 shows a method in which a UE that has reserved transmissionresource(s) informs another UE of the transmission resource(s), based onan embodiment of the present disclosure. The embodiment of FIG. 10 maybe combined with various embodiments of the present disclosure.

Specifically, for example, (a) of FIG. 10 shows a method for performingby a transmitting UE chain-based resource reservation bytransmitting/signaling location information of (maximum) 2 transmissionresources to receiving UE(s) through one SCI, in the case of a value ofK = 4. For example, (b) of FIG. 10 shows a method for performing by atransmitting UE chain-based resource reservation bytransmitting/signaling location information of (maximum) 3 transmissionresources to receiving UE(s) through one SCI, in the case of a value ofK = 4. For example, referring to (a) and (b) of FIG. 10 , thetransmitting UE may transmit/signal only location information of thefourth transmission-related resource to the receiving UE(s) through thefourth (or last) transmission-related PSCCH. For example, referring to(a) of FIG. 10 , the transmitting UE may transmit/signal to thereceiving UE(s) not only location information of the fourthtransmission-related resource but also location information of the thirdtransmission-related resource additionally through the fourth (or last)transmission-related PSCCH. For example, referring to (b) of FIG. 10 ,the transmitting UE may transmit/signal to the receiving UE(s) not onlylocation information of the fourth transmission-related resource butalso location information of the second transmission-related resourceand location information of the third transmission-related resourceadditionally through the fourth (or last) transmission-related PSCCH. Inthis case, for example, in (a) and (b) of FIG. 10 , if the transmittingUE may transmit/signal to the receiving UE(s) only location informationof the fourth transmission-related resource through the fourth (or last)transmission-related PSCCH, the transmitting UE may set or designate afield/bit of location information of unused or remaining transmissionresource(s) to a pre-configured value (e.g., 0). For example, in (a) and(b) of FIG. 10 , if the transmitting UE may transmit/signal to thereceiving UE(s) only location information of the fourthtransmission-related resource through the fourth (or last)transmission-related PSCCH, the transmitting UE may be set or designatea field/bit of location information of unused or remaining transmissionresource(s) to a pre-configured status/bit value indicating/representingthe last transmission (among 4 transmissions).

Meanwhile, for example, the transmitting UE may perform a reservation oftransmission resource(s) based on a block. Specifically, for example, ifthe transmitting UE reserves K transmission resources, the transmittingUE may transmit location information for K transmission resources toreceiving UE(s) through a SCI transmitted to the receiving UE(s) at any(or specific) transmission time or a time resource. That is, the SCI mayinclude location information for K transmission resources. For example,if the transmitting UE reserves K transmission resources related to aspecific TB, the transmitting UE may transmit location information for Ktransmission resources to receiving UE(s) through a SCI transmitted tothe receiving UE(s) at any (or specific) transmission time or a timeresource. That is, the SCI may include location information for Ktransmission resources. For example, (c) of FIG. 10 shows a method forperforming by the transmitting UE block-based resource reservation, bysignaling location information of 4 transmission resources to receivingUE(s) through one SCI, in the case of a value of K = 4.

For example, SL DRX configuration may include one or morepieces/elements of information listed below.

For example, SL drx-onDurationTimer may be information related to theduration at the beginning of a DRX Cycle. For example, the duration atthe beginning of a DRX Cycle may be information related to the durationin which the UE operates in the active mode to transmit or receivesidelink data.

For example, SL drx-SlotOffset may be information related to the delaybefore starting the drx-onDurationTimer of the DRX-on duration timer.

For example, SL drx-InactivityTimer may be information indicating theduration after the PSCCH occasion in which a PSCCH indicates a newsidelink transmission and reception for the MAC entity. For example,when the transmitting UE indicates a PSSCH transmission through a PSCCH,the transmitting UE may operate in an active mode while the SLdrx-InactivityTimer is operating/running, so that the transmitting UEcan transmit the PSSCH to a receiving UE. Also, for example, when thereceiving UE receives, through PSCCH reception, an indication that thetransmitting UE transmits the PSSCH, the receiving UE may operate in anactive mode while the SL drx-InactivityTimer is operating/running, sothat the receiving UE is the transmitting can receive PSSCH from atransmitting UE.

For example, the SL drx-RetransmissionTimer may be information relatedto the maximum duration until a retransmission is received. For example,the SL drx-RetransmissionTimer may be configured for each HARQ process.

For example, SL drx-LongCycleStartOffset information related to the LongDRX cycle and drx-StartOffset which defines the subframe where the Longand Short DRX Cycle starts

For example, SL drx-ShortCycle may be information related to the ShortDRX cycle. For example, the SL drx-ShortCycle may be optionalinformation.

For example, the SL drx-ShortCycleTimer may be information related tothe duration the UE shall follow the Short DRX cycle. For example, theSL drx-ShortCycleTimer may be optional information.

For example, the SL drx-HARQ-RTT-Timer may be information related to theminimum duration before an assignment for a HARQ retransmission isexpected by the MAC entity. For example, the SL drx-HARQ-RTT-Timer maybe configured for each HARQ process.

In the meantime, for example, when SL communication is performed basedon an SL HARQ feedback operation performing feedback of a NACK only(hereinafter, a NACK ONLY-based SL HARQ feedback operation), accordingto various embodiments of the present disclosure, re-set/extension of anSL DRX timer and/or of the active time may be performed. Here, forexample, the SL HARQ feedback operation may include a PSFCH transmissionand/or PSFCH reception. For example, the NACK ONLY-based SL HARQfeedback operation may be an operation of transmitting NACK informationto the TX UE only when the RX UE fails to decode/receive the PSSCHreceived from the TX UE.

According to an embodiment of the present disclosure, when a pluralityof PSFCH transmissions overlap at the same time point, some or all ofthe plurality of PSFCH transmissions may be skipped/omitted. Forexample, from the viewpoint of a specific UE, when a plurality of PSFCHtransmissions overlap on the same time point, some or all of a pluralityof PSFCHs may be skipped/omitted based on a priority of PSSCH and/or SLdata related to the PSFCH and the maximum number of PSFCHs capable ofsimultaneous transmission by the UE.

For example, from the viewpoint of a specific UE, when a PSFCHtransmission and a PSFCH reception overlap on the same time point, thePSFCH transmission or PSFCH reception may be skipped/omitted based on apriority of PSSCH and/or SL data related to PSFCH and the maximum numberof PSFCHs capable of simultaneous transmission by the UE.

For example, from the viewpoint of a specific UE, when a PSFCHtransmission and a UL control/data transmission overlap on the same timepoint, the PSFCH transmission may be skipped/omitted based on a priorityof PSSCH and/or SL data related to the PSFCH, a priority of ULcontrol/data, and the maximum number of PSFCHs capable of simultaneoustransmission by the UE. Here, for example, the UL control/data mayinclude a UL channel through which SL HARQ feedback, SL BSR, and/or SLSR are transmitted/piggybacked.

For example, from the viewpoint of a specific UE, when a PSFCH receptionand a UL transmission overlap on the same time point, PSFCH receptionmay be skipped/omitted based on a priority of PSSCH and/or SL datarelated to the PSFCH, a priority of UL control/data, and the maximumnumber of PSFCHs capable of simultaneous transmission by the UE Here,for example, the UL control/data may include a UL channel through whichSL HARQ feedback, SL BSR, and/or SL SR are transmitted/piggybacked.

For example, from the viewpoint of a specific UE, when atransmission/reception of NR PSFCH and a transmission/reception of LTESL channel/signal (e.g., PSCCH, PSSCH, SL synchronization signal)overlap on the same time point, the NR PSFCH transmission/reception maybe skipped/omitted based on a priority of NR PSSCH and/or NR SL datarelated to NR PSFCH, a priority of the LTE SL channel/signal, and themaximum number of PSFCHs capable of simultaneous transmission by the UE.

For example, when the RX UE performing an SL DRX operation performs aNACK ONLY-based PSFCH transmission operation, if the NACK transmissionis skipped/omitted due to one of the above-described examples, a TX UEmay assume that the RX UE has successfully received the MAC PDU and maynot perform an additional retransmission operation. At this time,nevertheless, since the RX UE has not yet succeeded in receiving the MACPDU, a problem of re-set/extension of an SL DRX timer and/or an activetime may occur. Here, for example, the problem may occur because whetheror not to perform re-set/extension of the SL DRX timer and/or activetime of the RX UE is determined based on reception/decoding failure forthe MAC PDU and not based on whether the NACK is actually transmittedthrough the PSFCH. In order to solve this problem, various embodimentsof the present disclosure to be described later may be applied.

For example, when a NACK ONLY-based SL HARQ feedback operation isperformed, the RX UE performing the SL DRX operation may performre-set/extension of the SL DRX timer and/or active time only when a NACKtransmission is actually performed through the PSFCH resource. Forexample, when a NACK ONLY-based PSFCH transmission operation isperformed in groupcast, the RX UE performing the SL DRX operation mayperform reset/extension of the SL DRX timer and/or active timer relatedto the SL HARQ process related to the NACK transmission only when theNACK transmission is actually performed through the PSFCH resource. Forexample, in the NACK ONLY-based SL HARQ feedback operation, when theNACK transmission is skipped/omitted, the RX UE may not perform thereset/extension of the SL DRX timer and/or active time related to the SLHARQ process related to the NACK transmission.

Also, for example, on the other hand, in case an ACK/NACK-based SL HARQfeedback operation is performed, regardless of whether or not the actualNACK is transmitted through a PSFCH resource, the RX UE performing theSL DRX operation may perform the reset/extension of the SL DRX timerand/or active time when it fails to receive/decode the MAC PDU. Here,for example, the ACK/NACK-based SL HARQ feedback operation may includean operation of transmitting ACK information to the TX UE when the RX UEsucceeds in decoding/receiving the PSSCH received from the TX UE, and anoperation of transmitting NACK information to the TX UE when the RX UEfails in decoding/receiving the PSSCH. For example, when anACK/NACK-based SL HARQ feedback operation is performed in groupcast, ifthe RX UE performing the SL DRX operation fails in receiving/decodingthe MAC PDU related to the PSFCH transmission even if the PSFCHtransmission is skipped/omitted, the RX UE may perform re-set/extensionof the SL DRX timer and/or active time related to the SL HARQ processrelated to the PSFCH transmission. Additionally, for example, when anACK/NACK-based SL HARQ feedback operation is performed, the RX UEperforming the SL DRX operation may perform re-set/extension of the SLDRX timer and/or active time even if the PSFCH transmission (e.g., ACKor NACK) is skipped/omitted. Here, for example, when an ACK/NACK-basedSL HARQ feedback operation is performed, even if the RX UE skips oromits the PSFCH transmission, since the TX UE considers it as DTX and/orNACK and performs a retransmission, in a duration in which there is noretransmission of the UE, a problem of meaninglessly performing aretransmission reception operation may not occur.

According to an embodiment of the present disclosure, an RX UEperforming a NACK ONLY-based SL HARQ feedback operation may skip/omit aNACK transmission due to a relatively high priority SL channel/signalreception operation. In this case, for example, after the RX UEchecks/detects whether a NACK transmission of another UE is performed ona PSFCH resource, if the NACK transmission of another UE is performed,although the RX UE itself does not perform a NACK transmission, an SLDRX Timer and/or active time reset/extension operation may be performed.For example, the SL channel/signal may include at least one of a PSFCHor an LTE SL channel/signal. For example, the LTE SL channel/signal mayinclude at least one of PSSCH, PSCCH, or SL synchronization signal.

For example, when the above-described embodiment of the presentdisclosure is applied, as one of examples in which the transmissionsoverlap, an RX UE performing a NACK ONLY-based SL HARQ feedbackoperation may skip/omit a NACK transmission due to a relatively highpriority SL channel/signal reception operation. In this case, forexample, on a PSFCH resource related to the NACK transmission, it ispossible to check/detect whether a NACK transmission by another memberUE in the same groupcast is performed. At this time, if the NACKtransmission of another member UE is performed, although the RX UEitself does not perform a NACK transmission, a re-set/extensionoperation of the SL DRX timer and/or active time related to the SL HARQprocess related to the NACK transmission re-set/extension operation canbe performed.

According to an embodiment of the present disclosure, a UE performing anSL DRX operation may consider a PSFCH transmission operation satisfyingthe following specific condition as a higher priority than other PSFCHreception operations. For example, the RX UE performing the SL DRXoperation may consider a PSFCH transmission and/or PSFCH receptionoperation satisfying the following specific condition as a higherpriority than other PSFCH reception and/or transmission operations.Here, for example, the other PSFCH reception and/or transmission may bea PSFCH reception and/or transmission related to a pre-configuredservice type. For example, the other PSFCH reception and/or transmissionmay be a PSFCH reception and/or transmission related to a priority of anLCH or service higher than a pre-configured threshold level. Forexample, the other PSFCH reception and/or transmission may be a PSFCHreception and/or transmission related to a QoS requirement (e.g.,reliability, latency) higher than a pre-configured threshold level. Forexample, the other PSFCH reception and/or transmission may be a PSFCHreception and/or transmission related to a QoS requirement (e.g.,reliability, latency) lower than a pre-configured threshold level.

For example, the RX UE performing the SL DRX operation may consider aPSFCH transmission and/or PSFCH reception operation satisfying thefollowing specific condition as a higher priority than a UL control/datatransmission and/or reception operation. Here, for example, the ULcontrol/data may include a UL channel through which SL HARQ feedback, SLBSR and/or SL SR are transmitted/piggybacked.

For example, the RX UE performing the SL DRX operation may consider aPSFCH transmission and/or PSFCH reception operation satisfying thefollowing specific condition as a higher priority than atransmission/reception operation for an LTE SL channel/signal (e.g.,PSCCH, PSSCH, SL synchronization signal).

For example, the specific condition may be related to a NACK ONLY-basedSL HARQ feedback. For example, when the RX UE transmits and/or receivesthe NACK ONLY-based SL HARQ feedback in groupcast, the RX UE maydetermine the transmission and/or reception to have a higher prioritythan other PSFCH transmission and/or reception operation.

For example, the specific condition may be related to an ACK/NACK-basedSL HARQ feedback. For example, when the RX UE transmits and/or receivesthe ACK/NACK-based SL HARQ feedback in groupcast, the RX UE maydetermine the transmission and/or reception to have a higher prioritythan other PSFCH transmission and/or reception operation.

For example, the specific condition may be related to an SL HARQfeedback transmission and/or reception. For example, when the RX UEtransmits and/or receives the SL HARQ feedback, the RX UE may determinethe transmission and/or reception to have a higher priority than otherPSFCH transmission and/or reception operation.

For example, the specific condition may be related to a groupcastcommunication. For example, when the RX UE performs transmission and/orreception for a PSFCH related to the groupcast communication, the RX UEmay determine the transmission and/or reception to have a higherpriority than other PSFCH transmission and/or reception operation. Here,for example, an SL channel/signal transmission and/or reception (e.g.,PSFCH transmission) related to the groupcast including a relativelygreat number of members may be considered a higher priority than atransmission and/or reception related to other groupcast. For example,an SL channel/signal transmission and/or reception (e.g., PSFCHtransmission) related to the groupcast including a greater number ofmembers than a pre-configured threshold may be considered a highpriority than a transmission/reception related to another groupcast,unicast or broadcast.

For example, the specific condition may be related to a unicastcommunication. For example, when the RX UE performs a transmissionand/or reception for a PSFCH related to the unicast communication, theRX UE may determine the transmission and/or reception to have a higherpriority than other PSFCH transmission and/or reception operation.

For example, the specific condition may be related to a broadcastcommunication. For example, when the RX UE performs a transmissionand/or reception for a PSFCH related to the broadcast communication, theRX UE may determine the transmission and/or reception to have a higherpriority than other PSFCH transmission and/or reception operation.

For example, the specific condition may be related to a PSFCHtransmission and/or reception of a pre-configured service type. Forexample, the specific condition may be related to a PSFCH transmissionand/or reception with a priority of an LCH or service higher than apre-configured threshold level. For example, the specific condition maybe related to a transmission and/or reception of a PSFCH with QoSrequirements (e.g., reliability, latency) higher than a pre-configuredthreshold level. For example, the specific condition may be related to atransmission and/or reception of a PSFCH with QoS requirements (e.g.,reliability, latency) lower than a pre-configured threshold level.

According to an embodiment of the present disclosure, the followingembodiments may be applied to the RX UE performing the SL DRX operationon a reserved resource (hereinafter, RSR_RSC) located after the SL DRXtimer and/or active time is expired or over. For example, the RSR_RSCmay be a reserved resource signaled by the previous SCI. For example,the RSR_RSC may be a reserved resource located after the SL DRX timerand/or active time related to the SL HARQ process is expired or over.Here, for example, the above-described embodiment of the presentdisclosure may be applied when the RX UE skips/omits the related PSFCHtransmission for a MAC PDU received on a reserved resource before theRSR_RSC. For example, the embodiment of the present disclosure describedabove may be applied when the RX UE skips/omits the related PSFCHtransmission (e.g., ACK information transmission) due to a relativelyhigh priority channel transmission and/or reception operation for a MACPDU successfully received on the reserved resource before the RSR_RSC.For example, the reserved resource before the RSR_RSC may be a reservedresource before the SL DRX timer related to the SL HARQ process isexpired or over. For example, the reserved resource before the RSR_RSCmay be a reserved resource within the active time interval/durationrelated to the SL HARQ process. For example, the above-describedembodiment of the present disclosure may be applied when the RX UEactually successfully receives a PSCCH and/or PSSCH retransmission fromthe TX UE on the RSR_RSC.

For example, when an embodiment of the present disclosure is applied,for a MAC PDU that has already been successfully received by the RX UE,the TX UE may consider it as DTX and/or NACK and perform aretransmission, thereby alleviating the problem of performingexcessively many or meaningless retransmissions. For example, when anembodiment of the present disclosure is applied, the RX UE may skip/omita PSFCH transmission for the successfully received MAC PDU, and the TXUE may consider it as DTX and/or NACK and perform a retransmission,thereby alleviating the problem of performing excessively many ormeaningless retransmissions. For example, when an embodiment of thepresent disclosure is applied, if the TX UE does not successfullyreceive the PSFCH of the ACK information actually transmitted by the RXUE, the TX UE may consider it as DTX and/or NACK and perform aretransmission, thereby alleviating the problem of performingexcessively many or meaningless retransmissions.

For example, the present disclosure may be applied for a least one of acase in which the RX UE performs an ACK/NACK-based SL HARQ feedbackoperation; a case in which a packet related to an LCH or service havinga priority higher than a pre-configured threshold level is transmitted;a case in which a packet related to an LCH or service with a prioritylower than a pre-configured threshold level is transmitted; a case inwhich a packet related to QoS requirements (e.g. latency, reliability,minimum communication range) higher than a pre-configured threshold istransmitted; a case in which a packet related to QoS requirements (e.g.latency, reliability, minimum communication range) lower than apre-configured threshold is transmitted; a case in which a congestionlevel in the resource pool (e.g., CBR) is higher than a pre-configuredthreshold; and/or a case in which the congestion level in the resourcepool (e.g., CBR) is lower than the pre-configured threshold.

For example, the RX UE may additionally perform a PSSCH and/or PSCCHdecoding on the RSR_RSC, and then transmit ACK information related to aPSFCH resource related to the RSR_RSC. For example, after the RX UEadditionally performs a PSSCH and/or PSCCH decoding related to the TX UEin a slot related to the RSR_RSC, ACK information may always betransmitted on the PSFCH resource related to the RSR_RSC. For example,the RX UE additionally performs the PSSCH and/or PSCCH decoding relatedto the TX UE on a slot related to RSR_RSC, and then, based on whetherthe actual PSSCH and/or PSCCH decoding succeeds, ACK/NACK informationmay be transmitted on the PSFCH resource related to the RSR_RSC. Forexample, the additional PSSCH and/or PSCCH decoding may be performed inthe frequency domain related to the RSR_RSC. For example, the additionalPSSCH and/or PSCCH decoding may be performed for all frequency domainswithin the resource pool.

Here, for example, when a PSCCH and/or PSSCH related to another TX UE isdetected/decoded on a slot related to the RSR_RSC, the RX UE may notre-set/extend an SL DRX timer and/or active time of an SL HARQ processrelated to the PSCCH and/or PSSCH.

Here, for example, when a PSCCH and/or PSSCH related to another TX UE isdetected/decoded on a slot related to the RSR_RSC, the RX UE mayre-set/extend an SL DRX timer and/or active time of an SL HARQ processrelated to the PSCCH and/or PSSCH.

For example, the RX UE does not additionally perform a PSSCH and/orPSCCH decoding on the RSR_RSC, and the RX UE may transmit ACKinformation on a PSFCH resource related to the RSR_RSC. For example, theRX UE may not additionally perform a PSSCH and/or PSCCH decoding relatedto the TX UE with respect to the RSR_RSC related frequency domain on theRSR_RSC related slot, and the RX UE may transmit ACK information on aPSFCH resource related to the RSR_RSC. For example, the RX UE may notadditionally perform a PSSCH and/or PSCCH decoding related to the TX UEwith respect to all frequency domains within the resource pool on theRSR_RSC related slot, and the RX UE may transmit ACK information on aPSFCH resource related to the RSR_RSC.

For example, the number of RSR_RSCs for which the RX UE performs a PSFCHtransmission and/or an ACK information transmission may be configureddifferently or independently based on a service type, priority, and/orcongestion level in the resource pool. Here, for example, the number ofRSR_RSCs may be the maximum number. For example, the number of RSR_RSCsmay be the minimum number. For example, the number of RSR_RSCs may be anaverage number.

In addition, for example, whether the RX UE applies the variousembodiments of the present disclosure described above based beconfigured based on: whether the TX UE is a UE performing an SL DRXoperation; whether the TX UE is a power saving UE; whether the RX UEperforms a PSFCH transmission related to the MAC PDU successfullyreceived on a reserved resource before an SL DRX timer related to the SLHARQ process related to the RSR_RSC expires; and/or whether the RX UEperforms ACK information transmission on the MAC PDU successfullyreceived on the reserved resource before the SL DRX timer related to theSL HARQ process related to the RSR_RSC expires.

For example, when the TX UE is a UE performing an SL DRX operationand/or a power saving UE, the RX UE may apply various embodiments of thepresent disclosure described above. For example, when the RX UE actuallytransmits ACK information for a MAC PDU successfully received on areserved resource before the SL DRX timer related to the SL HARQ processrelated to the RSR_RSC expires, the various embodiments of the presentdisclosure provide may not be applied to the RX UE. For example, whenthe RX UE actually transmits ACK information for a MAC PDU successfullyreceived on the reserved resource within an active timeinterval/duration related to the SL HARQ process before the RSR_RSC, thevarious embodiments of the present disclosure may not be applied to theRX UE.

For example, whether the various embodiments of the present disclosureare applied may be determined based on at least one of the followingelements/parameters comprising: a service type; LCH-related priority;service-related priority; QoS requirements (e.g., latency, reliability,minimum communication range); PQI parameters; an LCH/MAC PDUtransmission with HARQ feedback enabled; an LCH/MAC PDU transmissionwith HARQ feedback disabled; CBR measure of resource pool; an SL casttype (e.g., unicast, groupcast, broadcast); an SL groupcast HARQfeedback option (e.g., NACK ONLY based feedback, ACK/NACK basedfeedback, TX-RX distance based NACK ONLY feedback); an SL mode 1 CG type(e.g., SL CG type 1, SL CG type 2); an SL mode type (e.g., mode 1, mode2); a resource pool; whether a PSFCH resource is a configured resourcepool; a source ID; a destination ID; a source L2 ID; a destination L2ID; PC5 RRC connection link; an SL Link; connection state with the basestation (e.g., RRC CONNECTED state, IDLE state, INACTIVE state); an SLHARQ process; an SL HARQ process ID; whether the TX UE or the RX UEperforms SL DRX operation; whether it corresponds to a power saving UE;whether PSFCH TX and PSFCH RX overlap from a specific UE perspective;whether a plurality of PSFCH TXs that exceed UE capability overlap;whether PSFCH TX and/or PSFCH RX is omitted; whether the RX UE actuallysuccessfully received the PSCCH and/or PSSCH (re)transmission from theTX UE.

For example, parameter setting values related to various embodiments ofthe present disclosure may be determined based on at least one of thefollowing elements/parameters comprising: a service type; LCH-relatedpriority; service-related priority; QoS requirements (e.g., latency,reliability, minimum communication range); PQI parameters; an LCH/MACPDU transmission with HARQ feedback enabled; an LCH/MAC PDU transmissionwith HARQ feedback disabled; CBR measure of resource pool; an SL casttype (e.g., unicast, groupcast, broadcast); an SL groupcast HARQfeedback option (e.g., NACK ONLY based feedback, ACK/NACK basedfeedback, TX-RX distance based NACK ONLY feedback); an SL mode 1 CG type(e.g., SL CG type 1, SL CG type 2); an SL mode type (e.g., mode 1, mode2); a resource pool; whether a PSFCH resource is a configured resourcepool; a source ID; a destination ID; a source L2 ID; a destination L2ID; PC5 RRC connection link; an SL Link; connection state with the basestation (e.g., RRC CONNECTED state, IDLE state, INACTIVE state); an SLHARQ process; an SL HARQ process ID; whether the TX UE or the RX UEperforms SL DRX operation; whether it corresponds to a power saving UE;whether PSFCH TX and PSFCH RX overlap from a specific UE perspective;whether a plurality of PSFCH TXs that exceed UE capability overlap;whether PSFCH TX and/or PSFCH RX is omitted; whether the RX UE actuallysuccessfully received the PSCCH and/or PSSCH (re)transmission from theTX UE.

In addition, in various embodiments of the present disclosure, forexample, “configuration” or “designation” may mean that a base stationinforms the UE through a pre-defined channel/signal (e.g., SIB, RRC, MACCE). For example, the “configuration” or “designation” may mean a formatprovided through PRE-CONFIGURATION. For example, the “configuration” or“designation” may be a format in which the UE informs other UEs througha predefined channel/signal (e.g., SL MAC CE, PC5 RRC). Here, forexample, the channel/signal may include a channel/signal for a physicallayer or a higher layer.

Also, in various embodiments of the present disclosure, for example,“PSFCH” may be replaced with at least one of an NR PSSCH, an NR PSCCH,an NR SL SSB, an LTE PSSCH, an LTE PSCCH, an LTE SL SSB, and a ULchannel/signal.

In addition, various embodiments of the present disclosure may becombined with each other.

In various embodiments of the present disclosure, the aforementioned SLDRX timer may be used for the following purposes.

For example, the SL DRX on-duration timer may be used in a period inwhich a UE performing an SL DRX operation basically needs to operate asan active time in order to receive a PSCCH/PSSCH of a counterpart/peerUE.

For example, the SL DRX deactivation timer may be used in a period forextending the SL DRX on-duration period, which is a period in which a UEperforming an SL DRX operation basically needs to operate as an activetime to receive a PSCCH/PSSCH of a counterpart/peer UE. That is, forexample, the SL DRX on-duration timer may be extended by the SL DRXdeactivation timer period. In addition, when the UE receives a newpacket (e.g., a new PSSCH) from the counterpart/peer UE, the UE maystart the SL DRX deactivation timer to extend the SL DRX on-durationtimer.

For example, an SL DRX HARQ RTT timer may be used in a sleep modeoperation period until a UE performing SL DRX operation receives aretransmission packet (or PSSCH assignment) transmitted from acounterpart/peer UE. That is, for example, when the UE starts the SL DRXHARQ RTT timer, the UE may determine that the counterpart/peer UE willnot transmit a sidelink retransmission packet to itself until the SL DRXHARQ RTT timer expires, and accordingly, the UE may operate in a sleepmode during the corresponding timer.

For example, an SL DRX retransmission timer may be used in an activetime period for a UE performing an SL DRX operation to receive aretransmission packet (or PSSCH assignment) transmitted from acounterpart/peer UE. For example, during the SL DRX retransmission timerperiod, the UE may monitor a reception of a retransmission sidelinkpacket (or PSSCH assignment) transmitted by the counterpart/peer UE.

In addition, in the present disclosure, for example, an on-duration oran ‘Onduration’ may be an Active Time duration (i.e., a durationoperating in a wake-up state (an RF module being “on”) toreceive/transmit a wireless signal). For example, an off-duration or an‘Offduration may be a Sleep Time duration (i.e., a duration operating ina sleep mode (an RF module being “off”) for power saving, wherein thetransmitting UE may not operate in the sleep mode during the sleep timeduration, and wherein if necessary, even in the sleep time, it may beallowed to operate as an active time for a moment for a sensingoperation/transmission operation).

In the present disclosure, for example, “specific time” may be a time inwhich the UE operates as an active time for a predefined time in orderto receive a sidelink signal or sidelink data from a counterpart/peerUE. there is. For example, the “specific time” may be a time in whichthe UE operates as an active time as long as a timer (e.g., an SL DRXretransmission timer, an SL DRX inactivity timer, a timer enabling tooperate as an active time in the DRX operation of the RX UE) time toreceive a sidelink signal or sidelink data from a counterpart/peer UE.

FIG. 11 shows a procedure for a receiving UE to start an SL DRX-relatedtimer according to an embodiment of the present disclosure. Theembodiment of FIG. 11 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 11 , in step S1110, the receiving UE may obtain an SLDRX configuration. For example, the receiving UE may receive the SL DRXconfiguration from a base station. For example, the receiving UE mayreceive the SL DRX configuration from the transmitting UE. For example,the SL DRX configuration may include information related to a cyclerelated to the SL DRX and information related to an SL DRX-relatedtimer. For example, the SL DRX-related timer may include at least one ofan SL DRX on-duration timer, an SL DRX deactivation timer, an SL DRXHARQ RTT timer, or an SL DRX retransmission timer.

In step S1120, the receiving UE may receive first SCI for scheduling afirst PSSCH through the first PSCCH from the transmitting UE.

In step S1130, the receiving UE may receive second SCI and first datathrough the first PSSCH from the transmitting UE. For example, thereceiving UE may determine a first PSFCH resource based on an index of aslot and an index of a subchannel related to the first PSSCH.

In step S1140, the receiving UE may skip/omit a transmission of thefirst PSFCH related to the first PSSCH. For example, when a plurality ofPSFCH transmissions overlap on the same time point, based on a priorityof SL data related to the PSFCH and a maximum number of PSFCHs that thereceiving UE can transmit simultaneously, at least one PSFCHtransmission may be skipped/omitted from among the plurality of PSFCHtransmissions. For example, the at least one PSFCH transmission mayinclude a first PSFCH transmission.

For example, when the first PSFCH transmission and the PSFCH receptionoverlap on the same time point, the first PSFCH transmission may beskipped/omitted based on the priority of the SL data related to thePSFCH and the maximum number of PSFCHs that the receiving UE cantransmit simultaneously.

For example, when the first PSFCH transmission and a UL control/datatransmission overlap on the same time point, based on the priority ofthe SL data related to the PSFCH, the priority related to the ULtransmission, and the maximum number of PSFCHs that the receiving UE cantransmit simultaneously, the first PSFCH transmission may beskipped/omitted. Here, for example, the UL transmission may include a ULchannel through which SL HARQ feedback, SL BSR, and/or SL SR aretransmitted/piggybacked.

In step S1150, the receiving UE may start a first timer included in theSL DRX configuration based on skipping/omission of a first PSFCHtransmission related to the first PSSCH on the first PSFCH resource.

For example, the first PSFCH may include either an ACK or a NACK.

For example, the first timer may include at least one of an SL DRX HARQRTT timer, or an SL DRX retransmission timer.

For example, based on the reserved resource located after the firsttimer expires, the receiving UE may transmit an ACK to the transmittingUE.

For example, decoding of the first PSSCH may be additionally performedon a reserved resource located after the first timer expires. Forexample, based on a successful decoding, the receiving UE may transmitan ACK to the transmitting UE.

For example, the number of reserved resources located after the firsttimer expires may be configured differently based on at least one of aservice type, priority, or congestion in a resource pool.

FIG. 12 shows another procedure in which a receiving UE starts an SLDRX-related timer according to an embodiment of the present disclosure.The embodiment of FIG. 12 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 12 , in step S1210, the receiving UE may obtain an SLDRX configuration. For example, the receiving UE may receive the SL DRXconfiguration from the base station. For example, the receiving UE mayreceive the SL DRX configuration from the transmitting UE. For example,the SL DRX configuration may include information related to a cyclerelated to the SL DRX and information related to an SL DRX-relatedtimer. For example, the SL DRX-related timer may include at least one ofan SL DRX on-duration timer, an SL DRX deactivation timer, an SL DRXHARQ RTT timer, or an SL DRX retransmission timer.

In step S1220, the receiving UE may receive first SCI for scheduling afirst PSSCH through the first PSCCH from the transmitting UE. Thereceiving UE may receive second SCI and first data from the transmittingUE through the first PSSCH. For example, the receiving UE may determinethe first PSFCH resource based on an index of a slot and an index of asubchannel related to the first PSSCH. For example, the receiving UE mayperform ACK/NACK-based HARQ feedback through the first PSFCH.

In step S1230, the receiving UE may receive third SCI for scheduling asecond PSSCH through a second PSCCH from the transmitting UE. Thereceiving UE may receive fourth SCI and second data through the secondPSSCH from the transmitting UE. For example, the receiving UE maydetermine a second PSFCH resource based on an index of a slot and anindex of a subchannel related to the second PSSCH. For example, thereceiving UE may perform NACK ONLY-based HARQ feedback through thesecond PSFCH.

In step S1240, the receiving UE may skip/omit a first PSFCH transmissionrelated to the first PSSCH, and the receiving UE may skip/omit a secondPSFCH transmission related to the second PSSCH. In this case, forexample, the first PSFCH transmission may be skipped/omitted as in theexamples of step S1140 described above. For example, the second PSFCHtransmission may be skipped/omitted as in the examples of step S1140described above.

In step S1250, the receiving UE may start the first timer included inthe SL DRX configuration based on the skipping/omission of the firstPSFCH transmission related to the first PSSCH on the first PSFCHresource. For example, the receiving UE may not start a second timerincluded in the SL DRX configuration based on the skipping/omission ofthe second PSFCH transmission related to the second PSSCH on the secondPSFCH resource. For example, the first PSFCH may include either an ACKor a NACK. For example, the second PSFCH may include only a NACK. Forexample, the first timer may include at least one of an SL DRX HARQ RTTtimer or an SL DRX retransmission timer. For example, the second timermay include at least one of an SL DRX HARQ RTT timer or an SL DRXretransmission timer.

In step S1260, the receiving UE may start the second timer based on thetransmission of a third PSFCH related to second data by another UE. Forexample, another UE may be a UE performing the same group castcommunication as the receiving UE. For example, the third PSFCH mayinclude only a NACK. For example, if the third PSFCH transmissionrelated to the second data is not performed by another UE, step S1260may be skipped/omitted.

For example, based on a reserved resource located after the first timerexpires, the receiving UE may transmit an ACK to the transmitting UE.

For example, decoding of the first PSSCH may be additionally performedon a reserved resource located after the first timer expires. Forexample, based on the successful decoding, the receiving UE may transmitan ACK to the transmitting UE.

For example, the number of reserved resources located after the firsttimer expires may be configured differently based on at least one of aservice type, priority, or congestion in the resource pool.

FIG. 13 shows an example of a reserved resource in which a receiving UEis located after an SL DRX-related timer expires, according to anembodiment of the present disclosure. The embodiment of FIG. 12 may becombined with various embodiments of the present disclosure.

Referring to FIG. 13 , when the receiving UE skips/omits a first PSFCHtransmission for first data received from the transmitting UE, thereceiving UE may start a first SL DRX timer related to the first PSFCHtransmission. For example, the first SL DRX timer may be at least one ofan SL DRX HARQ RTT timer or an SL DRX retransmission timer. For example,a first SL DRX active time may be an active time related to the first SLDRX timer.

At this time, for example, in an ACK/NACK-based HARQ feedback, when thereceiving UE skips/omits the first PSFCH transmission (e.g., SL HARQ ACKor SL HARQ NACK), the transmitting UE may determine the first datarelated to the first PSFCH as discontinuous detection (DTX). Also, forexample, after the first SL DRX timer expires, the receiving UE maytransmit an ACK for the first data to the transmitting UE based on thereserved resource. Or, for example, the receiving UE performs decodingof the first data on a reserved resource, and if the decoding issuccessfully performed, the receiving UE may transmit an ACK for thefirst data to the transmitting UE based on the reserved resource afterthe first SL DRX timer expires.

Here, for example, the reserved resource may be located within a secondSL DRX active time. For example, the second SL DRX active time may be anactive time for an SL communication between the receiving UE and anotherUE, or an active time for transmitting and receiving data different fromthe first data.

For example, when detecting a PSCCH and/or PSSCH related to anothertransmitting UE on the reserved resource, the receiving UE may not startthe first SL DRX timer.

Additionally, for example, if the receiving UE does not transmit a PSFCHfor HARQ-enabled transmission, the receiving UE may still start the HARQRTT timer in a symbol or slot after the end of the PSFCH resource. Forexample, the receiving UE may not transmit the PSFCH due to UL/SLprioritization.

Additionally, for example, in NACK ONLY-based HARQ feedback of agroupcast communication, if a PSFCH transmission (e.g., NACK) isdropped, the SL DRX retransmission timer may not be started. Here, forexample, the PSFCH transmission may be dropped due to UL/SLprioritization.

FIG. 14 shows a method for a first device to start an SL DRX-relatedtimer, according to an embodiment of the present disclosure. Theembodiment of FIG. 14 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 14 , in step S1410, the first device 100 may obtain anSL sidelink discontinuous reception (SL DRX) configuration.

In step S1420, the first device 100 may receive first sidelink controlinformation (SCI) for scheduling a first physical sidelink sharedchannel (PSSCH) through a first physical sidelink control channel(PSCCH) from the second device 200.

In step S1430, the first device 100 may receive second SCI and firstdata from the second device 200 through the first physical sidelinkshared channel (PSSCH).

In step S1440, the first device 100 may determine a first physicalsidelink feedback channel (PSFCH) resource based on an index of a slotand an index of a subchannel related to the first PSSCH.

For example, based on skipping/omission of the a PSFCH transmissionrelated to a first PSSCH on the first PSFCH resource, a first timerincluded in the SL DRX configuration may be started.

For example, the first PSFCH may include either an acknowledgment (ACK)or a negative acknowledgment (NACK).

For example, the first timer may include at least one of an SL DRXhybrid automatic repeat request (HARQ) round trip time (RTT) timer or anSL DRX retransmission timer.

For example, the first device 100 may receive third SCI for scheduling asecond PSSCH through a second PSCCH. For example, the first device 100may receive fourth SCI and second data through the second PSSCH. Forexample, the first device 100 may determine a second PSFCH resourcebased on an index of a slot and an index of a subchannel related to thesecond PSSCH. For example, based on the skipping/omission of the secondPSFCH transmission related to the second PSSCH on the second PSFCHresource, a second timer included in the SL DRX configuration may not bestarted. For example, the second PSFCH may include only a NACK. Forexample, the second timer may include at least one of an SL DRX HARQ RTTtimer and an SL DRX retransmission timer.

For example, the second timer may be started based on the transmissionof the third PSFCH related to the second data by a third device. Forexample, the third device may be a device that performs the same groupcast communication as the first device.

For example, the ACK may be transmitted based on a reserved resourcelocated after the first timer expires.

For example, decoding of the first PSSCH may be additionally performedon a reserved resource located after the first timer expires. Forexample, an ACK may be transmitted based on the successful decoding.

For example, the number of reserved resources located after theexpiration of the first timer may be configured differently based on atleast one of a service type, priority, or congestion in the resourcepool.

For example, based on a priority of a third PSFCH transmissionoverlapping the second PSFCH transmission being higher than a priorityof the second PSFCH transmission, the second PSFCH transmission may beskipped/omitted. For example, the second PSFCH transmission and thethird PSFCH transmission may be related to a groupcast communication.For example, the number of groupcast members related to the third PSFCHtransmission may be greater than the number of groupcast members relatedto the second PSFCH transmission.

The above-described embodiment may be applied to various devices to bedescribed below. For example, the processor 102 of the first apparatus100 may obtain a sidelink discontinuous reception (SL DRX)configuration. And, for example, the processor 102 of the first device100 is configured to control a transceiver 106 to receive first sidelinkcontrol information (SCI) for scheduling a first physical sidelinkshared channel (PSSCH) through a first physical sidelink control channel(PSCCH) from a second device. And, for example. The processor 102 of thefirst device 100 is configured to control the transceiver 106 to receivesecond SCI and first data from the second device through the firstPSSCH. The processor 102 of the first device 100 is configured tocontrol the transceiver 106 to receive determine a first physicalsidelink feedback channel (PSFCH) resource based on an index of a slotand an index of a subchannel which are related to the first PSSCH. Forexample, a first timer included in the SL DRX configuration is startedbased on skipping of a first PSFCH transmission related to the firstPSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a first device forperforming wireless communication may be provided. For example, thefirst device may include one or more memories for storing instructions;one or more transceivers; and one or more processors connecting the oneor more memories and the one or more transceivers. For example, the oneor more processors execute the instructions to obtain a sidelinkdiscontinuous reception (SL DRX) configuration; receive first sidelinkcontrol information (SCI) for scheduling a first physical sidelinkshared channel (PSSCH) through a first physical sidelink control channel(PSCCH) from a second device; and receiving second SCI and first datafrom the second device through the first PSSCH; and determine a firstphysical sidelink feedback channel (PSFCH) resource based on an index ofa slot and an index of a subchannel which are related to the firstPSSCH. For example, a first timer included in the SL DRX configurationis started based on skipping of a first PSFCH transmission related tothe first PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, an apparatusconfigured to control the first UE may be provided. For example, one ormore processors; and one or more memories operably coupled by the one ormore processors and storing instructions. For example, the one or moreprocessors execute the instructions to obtain a sidelink discontinuousreception (SL DRX) configuration; receive first sidelink controlinformation (SCI) for scheduling a first physical sidelink sharedchannel (PSSCH) through a first physical sidelink control channel(PSCCH) from a second UE; receive second SCI and first data from thesecond UE through the first PSSCH; and determine a first physicalsidelink feedback channel (PSFCH) resource based on an index of a slotand an index of a subchannel which are related to the first PSSCH. Forexample, wherein a first timer included in the SL DRX configuration isstarted based on skipping of a first PSFCH transmission related to thefirst PSSCH on the first PSFCH resource.

According to an embodiment of the present disclosure, a non-transitorycomputer readable medium (CRM) storing instructions may be provided. Forexample, the instructions, when executed, cause the first device to:obtain a sidelink discontinuous reception (SL DRX) configuration;receive first sidelink control information (SCI) for scheduling a firstphysical sidelink shared channel (PSSCH) through a first physicalsidelink control channel (PSCCH) from a second device; receive secondSCI and first data from the second device through the first PSSCH; anddetermine a first physical sidelink feedback channel (PSFCH) resourcebased on an index of a slot and an index of a subchannel which arerelated to the first PSSCH. For example, a first timer included in theSL DRX configuration is started based on skipping of a first PSFCHtransmission related to the first PSSCH on the first PSFCH resource.

FIG. 15 shows a method for starting an SL DRX timer according to anembodiment of the present disclosure. The embodiment of FIG. 15 may becombined with various embodiments of the present disclosure.

Referring to FIG. 15 , in step S1510, the second device 200 may transmitfirst sidelink control information (SCI) for scheduling a first physicalsidelink shared channel (PSSCH) through a first physical sidelinkcontrol channel (PSCCH) to the first device 100.

In step S1520, the second device 200 may transmit the second SCI andfirst data to the first device 100 through the first physical sidelinkshared channel (PSSCH).

For example, an SL sidelink discontinuous reception (DRX) configurationmay be obtained.

For example, a first physical sidelink feedback channel (PSFCH) resourcemay be determined based on an index of a slot related to the first PSSCHand an index of a subchannel.

For example, based on skipping/omission of the first PSFCH transmissionrelated to the first PSSCH on a first PSFCH resource, a first timerincluded in the SL DRX configuration may be started.

For example, the first PSFCH may include either an acknowledgment (ACK)or a negative acknowledgment (NACK).

For example, the first timer may include at least one of an SL DRXhybrid automatic repeat request (HARQ) round trip time (RTT) timer or anSL DRX retransmission timer.

For example, the ACK may be transmitted based on a reserved resourcelocated after the first timer expires.

For example, decoding of the first PSSCH may be additionally performedon a reserved resource located after the first timer expires. Forexample, an ACK may be transmitted based on the successful decoding.

For example, the number of reserved resources located after theexpiration of the first timer may be configured differently based on atleast one of a service type, priority, or congestion in the resourcepool.

The above-described embodiment may be applied to various devices to bedescribed below. First, for example, the processor 202 of the seconddevice 200 may be configured to control the transceiver 206 to transmitfirst sidelink control information (SCI) for scheduling a first physicalsidelink shared channel (PSSCH) through a first physical sidelinkcontrol channel (PSCCH) to a first device 100. And, for example, theprocessor 202 of the second device 200 may be configured to control thetransceiver 206 to transmit second SCI and first data to the firstdevice 100 through the first PSSCH.

According to an embodiment of the present disclosure, a second devicefor performing wireless communication may be provided. For example, thesecond device may include one or more memories to store instructions;one or more transceivers; and one or more processors connecting the oneor more memories and the one or more transceivers. For example, the oneor more processors execute the instructions to transmit first sidelinkcontrol information (SCI) for scheduling a first physical sidelinkshared channel (PSSCH) through a first physical sidelink control channel(PSCCH) to a first device; and transmit second SCI and first data to thefirst device through the first PSSCH. For example, a sidelinkdiscontinuous reception (SL DRX) configuration is obtained. For example,a first physical sidelink feedback channel (PSFCH) resource isdetermined based on an index of a slot and an index of a subchannelwhich are related to the first PSSCH. For example, a first timerincluded in the SL DRX configuration is started based on skipping of afirst PSFCH transmission related to the first PSSCH on the first PSFCHresource.

Various embodiments of the present disclosure may be combined with eachother.

Various embodiments of the present disclosure may be implementedindependently. Alternatively, various embodiments of the presentdisclosure may be implemented in combination with or merged with eachother. For example, various embodiments of the present disclosure havebeen described based on the 3GPP system for convenience of description,but various embodiments of the present disclosure may be extendable tosystems other than the 3GPP system. For example, various embodiments ofthe present disclosure are not limited only to direct communicationbetween UEs, and may be used in uplink or downlink, and in this case, abase station or a relay node may use the method proposed according tovarious embodiments of the present disclosure. For example, informationrelated to whether the method according to various embodiments of thepresent disclosure is applied may be provided by the base station to theUE or the second device 200 to the receiving UE using a predefinedsignal (e.g., a physical layer), signal or higher layer signal). Forexample, information related to rules according to various embodimentsof the present disclosure may be defined such that the base station maynotify the terminal or the second device 200 to the receiving UE througha pre-defined signal (e.g., a physical layer signal or a higher layersignal).

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 16 shows a communication system 1, based on an embodiment of thepresent disclosure. The embodiment of FIG. 16 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 16 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150b. For example, thewireless communication/connections 150 a and 150b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 17 shows wireless devices, based on an embodiment of the presentdisclosure. The embodiment of FIG. 17 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 17 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100x and theBS 200} and/or {the wireless device 100x and the wireless device 100x}of FIG. 16 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 18 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure. The embodiment of FIG. 18may be combined with various embodiments of the present disclosure.

Referring to FIG. 18 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 18 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 17 . Hardwareelements of FIG. 18 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 17 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 17. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 17 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 17 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 18 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 18 . For example, the wireless devices(e.g., 100 and 200 of FIG. 17 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 19 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 16 ). The embodiment of FIG. 19 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 19 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 17 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 17 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 17 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 16 ), the vehicles (100b-1 and 100 b-2 of FIG. 16 ), the XRdevice (100 c of FIG. 16 ), the hand-held device (100 d of FIG. 16 ),the home appliance (100 e of FIG. 16 ), the IoT device (100 f of FIG. 16), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 16 ), the BSs (200 of FIG. 16 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 19 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 19 will be described indetail with reference to the drawings.

FIG. 20 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT). The embodiment of FIG. 20 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 20 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to140c correspond to theblocks 110 to 130/140 of FIG. 19 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 21 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc. The embodiment of FIG. 21 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 21 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 19 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is:
 1. A method for performing wireless communication by a first device, the method comprising: obtaining a sidelink discontinuous reception (SL DRX) configuration; receiving first sidelink control information (SCI) for scheduling a first physical sidelink shared channel (PSSCH) through a first physical sidelink control channel (PSCCH) from a second device; receiving second SCI and first data from the second device through the first PSSCH; and determining a first physical sidelink feedback channel (PSFCH) resource based on a slot and a subchannel of the first PSSCH, wherein a first timer included in the SL DRX configuration is started based on skipping of a first PSFCH transmission related to the first PSSCH on the first PSFCH resource.
 2. The method of claim 1, wherein the first PSFCH includes either an acknowledgment (ACK), or a negative acknowledgment (NACK).
 3. The method of claim 1, wherein the first timer includes at least one of an SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer, or an SL DRX retransmission timer.
 4. The method of claim 1, further comprising: receiving third SCI for scheduling a second PSSCH through a second PSCCH; receiving fourth SCI and second data through the second PSSCH; and determining a second PSFCH resource based on a slot and a subchannel of the second PSSCH, wherein a second timer included in the SL DRX configuration is not started based on skipping of a second PSFCH transmission related to the second PSSCH on the second PSFCH resource.
 5. The method of claim 4, wherein the second PSFCH includes only a NACK.
 6. The method of claim 4, wherein the second timer includes at least one of an SL DRX HARQ RTT timer, or an SL DRX retransmission timer.
 7. The method of claim 4, wherein the second timer is started based on a third PSFCH related to the second data being transmitted by a third device, wherein the third device is a device performing same group cast communication as the first device.
 8. The method of claim 1, wherein an ACK is transmitted based on a reserved resource located after the first timer expires.
 9. The method of claim 1, wherein decoding of the first PSSCH is additionally performed on a reserved resource located after the first timer expires.
 10. The method of claim 9, wherein an ACK is transmitted based on the decoding being successful.
 11. The method of claim 1, wherein a number of reserved resources located after the first timer expires is configured differently based on at least one of a service type, priority, or congestion in a resource pool.
 12. The method of claim 4, wherein, based on a priority of a third PSFCH transmission overlapping the second PSFCH transmission being higher than a priority of the second PSFCH transmission, the second PSFCH transmission is skipped.
 13. The method of claim 12, wherein the second PSFCH transmission and the third PSFCH transmission are related to groupcast communication, and wherein a number of groupcast members related to the third PSFCH transmission is greater than a number of groupcast members related to the second PSFCH transmission.
 14. A first device configured to perform wireless communication, the first device comprising: at least one transceiver; at least one processor; and at least one memory connected to the at least one processor and storing instructions that, based on being executed, cause the at least one processor to perform operations comprising: obtaining a sidelink discontinuous reception (SL DRX) configuration; receiving first sidelink control information (SCI) for scheduling a first physical sidelink shared channel (PSSCH) through a first physical sidelink control channel (PSCCH) from a second device; receiving second SCI and first data from the second device through the first PSSCH; and determining a first physical sidelink feedback channel (PSFCH) resource based on a slot and a subchannel of the first PSSCH, wherein a first timer included in the SL DRX configuration is started based on skipping of a first PSFCH transmission related to the first PSSCH on the first PSFCH resource.
 15. The first device of claim 14, wherein the first PSFCH includes either an acknowledgment (ACK), or a negative acknowledgment (NACK).
 16. The first device of claim 14, wherein the first timer includes at least one of an SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer, or an SL DRX retransmission timer.
 17. A processing device configured to control a first device, the processing device comprising: at least one processor; and at least one memory connected to the at least one processor and storing instructions that, based on being executed, cause the at least one processor to perform operations comprising: obtaining a sidelink discontinuous reception (SL DRX) configuration; receiving first sidelink control information (SCI) for scheduling a first physical sidelink shared channel (PSSCH) through a first physical sidelink control channel (PSCCH) from a second device; receiving second SCI and first data from the second device through the first PSSCH; and determining a first physical sidelink feedback channel (PSFCH) resource based on a slot and a subchannel of the first PSSCH, wherein a first timer included in the SL DRX configuration is started based on skipping of a first PSFCH transmission related to the first PSSCH on the first PSFCH resource.
 18. The processing device of claim 17, wherein the first PSFCH includes either an acknowledgment (ACK), or a negative acknowledgment (NACK).
 19. The processing device of claim 17, wherein the first timer includes at least one of an SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer, or an SL DRX retransmission timer. 